It has been far from the start to the campaign the Croatian would have wanted, losing their last four league matches against Manchester City, Watford, West Bromwich Albion and the 3-0 defeat to Southampton last Sunday.
The pressure has beginning to grow on the coach, but believes that a win over Aitor Karanka's side will get their season back on track.
“I am concerned. If we are talking about the last five Premier League games it's simply not the way we expected it to be, it's definitely not good and that's why the only thing we are thinking about is the game on Saturday against Middlesbrough." Bilic told whufc.com.
He continued to say that "with one win we can build everything back and we have a good chance at home. We are a team that is alive, the players are good together, they train, they listen, we talk about it a lot."
Bilic concluded: “Of course - you are questioning yourself when you are doing great so of course I am asking myself a lot of questions. I did last year when we were doing well and one short spell when we were doing not so well. We were seventh so that means we were losing games as well."
Along with their poor form, they have suffered a number of injuries, which has allowed the likes of Sam Byram have regular play-time. The full-back admitted that he learned how to handle pressure during his time with former club Leeds United.
“This is a massive chance for us to turn things around. We have been working on things during the week and will take that into the game," Byram told the club's website. “From seeing the week of training we have had I can say the lads have the hunger to get the win and there is no doubt there will be 100 per cent effort at the weekend.”
Byram concluded: "We all know the situation is not great at the moment but we had a positive meeting and with a couple of good results we could be mid-table because the table is so tight at the moment."
West Ham United will take on Middlesbrough at the London Stadium on Saturday, October 1 with kick-off at 3pm BST.